DE102007020569A1 - Process for the preparation of aminoalkylpolysiloxanes - Google Patents

Abstract

Process for the preparation of aminoalkylpolysiloxanes by (i) mixing of (1) aminoalkylsilane hydrolyzate of the general formula (AR <SUB> a </ SUB> SiO <SUB> (3-a) / 2 </ SUB>) <SUB> m </ SUB> (R <SUP> 1 </ SUP> O <SUB> 1/2 </ SUB>) <SUB> p </ SUB> (I) and (2) linear and branched organopolysiloxane of the general formula $ F1 and to A dispersion is obtained, wherein R and R <SUP> 1 </ SUP> have the meaning given in the claim, A is a monovalent SiC-bonded hydrocarbon radical containing 1 to 4 separate basic nitrogen atoms, a is 0 or 1, m 2 to 500, p is at least 2, x is 0, 1, 2 or 3 and y is 0 or 1, with the proviso that on average at least 10 Si atoms per molecule are contained in the organopolysiloxane (2) (ii) Reaction of aminoalkyl silane hydrolyzate ( 1) and organopolysiloxane (2) in the dispersion in the presence of a basic catalyst (3) until a substantially clear mixture is obtained, and (iii) stopping the reaction by neutralization of the basic catalyst sector (3).

Description

The The invention relates to a process for the preparation of aminoalkylpolysiloxanes.

The usual practiced process for the preparation of aminoalkyl functional Siloxanes are based on aminoalkylsilanes which are terminated in OH or Me Polysiloxanes are equilibrated. In individual versions These methods differ mostly in the type and amount of used Catalysts necessary for the adjustment of an equilibrium are, in the way of their neutralization at the end of the reaction and possibly in the use of various carbinols for endstopper and Stabilization of the resulting polymers. For aminoalkylpolydimethylsiloxanes the equilibration means at the same time the formation of low molecular weight volatile by-products used in most applications are undesirable and therefore in a separate physical Process must be removed. This means increased Manufacturing costs usually associated with yield losses and is especially economically unattractive for commodities. For this reason are technical optimization measures in this field focused on the proportion of volatile by-products to minimize.

As in EP 382 366 A This can be achieved by using certain hydroxide catalysts which catalyze only the condensation of linear silanol-terminated diorganopolysiloxanes. The linear diorganopolysiloxanes may also have functional groups, such as aminoalkyl groups. OH-blocked aminoalkylsiloxanes must already be used as "raw materials" in this process, although it is not described how they can be produced in a low-loss manner.

US 3,890,269 (corresponding DE 2 339 761 A ) describes a process for the preparation of aminoalkylsiloxanes in which cyclic siloxanes are equilibrated with aminoalkylsilanes or their hydrolyzates in the presence of an alkali metal catalyst, which amounts to substantial amounts of volatile siloxanes during the equilibration.

It was the object to provide a process for the preparation of aminoalkylpolysiloxanes in which the reaction times are short, are obtained in the aminoalkylpolysiloxanes, which have a low residual volatility, in particular a low content of cyclic siloxanes, such as cyclooctamethyltetrasiloxane (D ₄ ), and the storage stable and, in particular, linear silanol-terminated aminoalkylpolysiloxanes (Si-OH) are obtained.

• (i) Mischen von
• (1) Aminoalkylsilanhydrolysat der allgemeinen Formel (AR_aSiO_(3-a)/2)_m(R¹O_1/2)_p (I)und
• (2) Organopolysiloxan aus Einheiten der allgemeinen Formel
  
  und bis eine Dispersion erhalten wird, wobei R gleich oder verschieden ist und einen einwertigen, gegebenenfalls halogenierten Kohlenwasserstoffrest mit 1 bis 18 Kohlenstoffatomen bedeutet, R¹ ein Wasserstoffatom oder einen Alkylrest mit 1 bis 4 Kohlenstoffatomen, der ein oder zwei separate Sauerstoffatome enthalten kann, bedeutet, vorzugsweise ein Wasserstoffatom ist, A einen einwertigen SiC-gebundenen Kohlenwasserstoffrest, der 1 bis 4 separate basische Stickstoffatome enthält, bedeutet, a 0 oder 1, vorzugsweise 1, ist, m eine ganze Zahl von 2 bis 500, vorzugsweise von 2 bis 50, ist und p eine ganze Zahl von mindestens 2 bedeutet, vorzugsweise eine ganze Zahl von 2 bis 10 ist, x 0, 1, 2 oder 3 ist, y 0 oder 1 ist, mit der Maßgabe, dass durchschnittlich mindestens 10 Si-atome, vorzugsweise mindestens 20 Si-atome, pro Molekül im Organopolysiloxan (2) enthalten sind,
• (ii) Reaktion von Aminoalkylsilanhydrolysat (1) und Organopolysiloxan (2) in der Dispersion in Gegenwart eines basischen Katalysators (3) bis eine weitgehend klare Mischung erhalten wird und
• (iii) Stoppen der Reaktion durch Neutralisation des basischen Katalysators (3).

The invention relates to a process for the preparation of aminoalkylpolysiloxanes by

• (i) mixing
• (1) Aminoalkylsilane hydrolyzate of the general formula (AR _a SiO _{(3-a) / 2} ) _m (R ¹ O _1/2 ) _p (I) and
• (2) Organopolysiloxane of units of the general formula
  
  and until a dispersion is obtained, wherein R is the same or different and is a monovalent, optionally halogenated hydrocarbon radical having 1 to 18 carbon atoms, R ^{1 is} a hydrogen atom or an alkyl radical having 1 to 4 carbon atoms, which may contain one or two separate oxygen atoms A is a monovalent SiC-bonded hydrocarbon radical containing 1 to 4 separate basic nitrogen atoms, a is 0 or 1, preferably 1, m is an integer from 2 to 500, preferably from 2 to 50, and p is an integer of at least 2, preferably an integer of 2 to 10, x is 0, 1, 2 or 3, y is 0 or 1, provided that an average of at least 10 Si atoms, preferably at least 20 Si atoms, per molecule in the organopolysiloxane (2) are contained,
• (ii) reaction of aminoalkyl silane hydrolyzate (1) and organopolysiloxane (2) in the dispersion in the presence of a basic catalyst (3) until a substantially clear mixture is obtained, and
• (iii) stopping the reaction by neutralization of the basic catalyst (3).

Preferably, in step (i) an organopolysiloxane (2) is used which contains on average at least two R ¹ O radicals per molecule.

It is well known prior art that equilibrations Slower under cleavage and reformation of Si-O-Si bonds proceed as condensation reactions of siloxanols. Surprisingly but was found that in the reaction of Aminoalkylsilanhydrolysat (1) even in the silanol form with organopolysiloxane (2) as well in the silanol form, the aminoalkyl siloxane in the form of separated aminoalkyl silane units is incorporated into the organopolysiloxane (2) before any appreciable condensation the siloxanols are used. Equally surprising is that this rapid redistribution reaction only very small amounts volatile cyclosiloxanes produced.

The inventive method has the advantage that Aminoalkylpolysiloxanes are obtained which have a low residual volatility, d. H. a low content of cyclic siloxanes, preferably below 1% by weight, preferably below 0.7% by weight.

Across from often practiced condensation method of aminoalkylpolysiloxanes with polydimethylsiloxane diols has the inventive Process has the advantage that the product viscosities over the Educts are only moderately elevated. The viscosity quotient of product / starting material mixture is mostly below 4 while keeping it is usually above 10 in condensation processes. If although this is desired in the inventive Procedure by extending the reaction time also possible for reasons of ease of use, however, are usually. lower Product viscosities desired. condensation process inevitably involve the connection of several educts (under Formation of very small fission products), so that always a considerable Viscosity increase results.

In a particular way, the present process is suitable for the preparation of aminoalkylsiloxanediols having virtually quantitative SiOH stoppering of the chain ends, which can hardly be achieved with the use of aminoalkylsilanes or can be achieved with complicated sequential procedures. Aminoalkylpolysiloxanes of this type are surprisingly stable on storage and are used to prepare aminoalkylsiloxane high polymers, e.g. B. used in emulsion, as in WO 2006/015740 described.

In this case, Aminoalkylsilanhydrolysat (1) is used with R ¹ O termination, wherein R ¹ is hydrogen. The proportion of R ¹ in the meaning of hydrogen is then preferably greater than 90 mol%, preferably greater than 98 mol%, particularly preferably about 100 mol%. The same applies to the end groups of the organopolysiloxane (2).

Examples for hydrocarbon radicals R are alkyl radicals, such as the methyl, Ethyl, n-propyl, iso-propyl, 1-n-butyl, 2-n-butyl, iso-butyl, tert-butyl, n-pentyl, iso-pentyl, neo-pentyl, tert-pentyl, Hexyl radicals, such as the n-hexyl radical, heptyl radicals, such as the n-heptyl radical, Octyl radicals, such as the n-octyl radical and iso-octyl radicals, such as the 2,2,4-trimethylpentyl radical, Nonyl radicals, such as the n-nonyl radical, decyl radicals, such as the n-decyl radical, Dodecyl radicals, such as the n-dodecyl radical, and octadecyl radicals, such as n-octadecyl radical; Cycloalkyl radicals, such as cyclopentyl, cyclohexyl, Cycloheptyl and methylcyclohexyl radicals; Aryl radicals, such as the phenyl, Naphthyl, anthryl and phenanthryl; Alkaryl radicals, such as o-, m-, p-tolyl radicals, xylyl radicals and ethylphenyl radicals; and aralkyl radicals, such as the benzyl radical, the α- and the β-phenylethyl radical.

Examples halogenated radicals R are haloalkyl radicals such as 3,3,3-trifluoro-n-propyl radical, the 2,2,2,2 ', 2', 2'-hexafluoroisopropyl radical, the heptafluoroisopropyl radical and haloaryl radicals, such as the o-, m- and p-chlorophenyl.

Prefers the radical R is a monovalent hydrocarbon radical having 1 to 6 carbon atoms, with the methyl radical being particularly preferred is.

Examples of R ¹ are H-, CH ₃ -, CH ₃ CH ₂ -, (CH ₃ ) ₂ CH-, CH ₃ CH ₂ CH ₂ -, CH ₃ CH ₂ CH ₂ CH ₂ -, CH ₃ CH ₂ OCH ₂ CH ₂ -, CH ₃ CH ₂ OCH ₂ - and CH ₃ OCH ₂ CH ₂ radicals.

Preferably, A in formula (I) is a radical of the formula -R ² - [NR ³ -R ⁴ -] _g NR ³ ₂ . where R ^{2 is} a divalent linear or branched hydrocarbon radical having 1 to 18 carbon atoms,
R ^{3 has} the meaning of R ¹ or denotes an acyl radical, preferably a hydrogen atom,
R ^{4 is} a divalent hydrocarbon radical having 1 to 6 carbon atoms and
g is 0, 1, 2, 3 or 4, preferably 0 or 1.

Preferred examples of radicals A are:
H ₂ N (CH ₂ ) ₃ -
H ₂ N (CH ₂ ) ₂ NH (CH ₂ ) ₃ -
H ₂ N (CH ₂ ) ₂ NH (CH ₂ ) CH (CH ₃ ) CH ₂ -
(Cyclohexyl) NH (CH ₂ ) ₃ -
CH ₃ NH (CH ₂ ) ₃ -
(CH ₃ ) ₂ N (CH ₂ ) ₃ -
CH ₃ CH ₂ NH (CH ₂ ) ₃ -
(CH ₃ CH ₂ ) ₂ N (CH ₂ ) ₃ -
CH ₃ NH (CH ₂ ) ₂ NH (CH ₂ ) ₃ -
(CH ₃ ) ₂ N (CH ₂ ) ₂ NH (CH ₂ ) ₃ -
CH ₃ CH ₂ NH (CH ₂ ) ₂ NH (CH ₂ ) ₃ -
(CH ₃ CH ₂ ) ₂ N (CH ₂ ) ₂ NH (CH ₂ ) ₃ -
and their partially or fully acetylated forms.

Particularly preferred examples of radicals A are:
H ₂ N (CH ₂ ) ₃ -
H ₂ N (CH ₂ ) ₂ NH (CH ₂ ) ₃ -
(Cyclohexyl) NH (CH ₂ ) ₃ -
(Acetyl) -NH (CH ₂ ) ₂ NH (CH ₂ ) ₃ -
(Acetyl) -NH (CH ₂ ) ₂ N (acetyl) (CH ₂ ) ₃ -

Prefers become the Aminoalkylsilanhydrolysate (1) from Aminoalkylfunktionellen Dialkoxysilanes, such as aminopropylmethyldimethoxysilane or aminoethylaminopropylmethyldimethoxysilane, produced by hydrolysis in water. This special group of substances has linear structure with preferably 2 to 50 siloxy units. aminoalkylsilane (1) can be used basically with any degree of polymerization become. For handling reasons but are viscosities below 10000 mPa · s at 25 ° C, in particular Hydrolysates with viscosities below 2000 mPa · s at 25 ° C.

The Aminoalkylsilane hydrolysates (1) preferably have amine group concentrations from usually 5 to about 12 mEqu./g. The remainder A may be prim., Sec. Or / and tert. Amine groups included.

Therefore, as Aminoalkylsilanhydrolysate (1) are preferably those of the general formula HO (ARSiO) _m H (III) used
where R, A and m have the meaning given above.

Preferred organopolysiloxanes (2) are those of the general formula HO (R ₂ SiO) _n H (IV) used
where R has the meaning given above and
n is an integer from 20 to 500.

Usually mixtures (1) and (2) are not homogeneous, but even in the heat turbid two-phase mixtures. By producing the smallest possible particles of the dispersed phase, the dispersion produced is prevented from decomposing into two macrophases. Due to the concomitant generation of large interfaces between dispersed and continuous phase, a maximum reaction rate and a controllability / reproducibility of the reaction is ensured beyond. This must be sen average particle sizes of preferably less than 1 mm are generated. Preferably, the dispersed phase has an average particle size of less than 100 microns, more preferably less than 10 microns, most preferably less than 1 micron. The dispersions are preferably no longer transparent in a layer thickness of more than 2 cm. No longer transparent means that a barcode is no longer recognizable. In order to achieve these particle sizes, various methods can be used to enter the required energy / work into the system. These may be conventional stirring and / or mixing units. Furthermore, dispersing aggregates can be used. In principle, all known from the prior art homogenizers come into question, such as. B. Hochgeschwindigkeitsrührwerke, high-performance dispersing (eg. For example, those available under the trademark IKA Ultra-Turrax ^®), Dissolversysteme and other rotor-stator homogenizers and high pressure homogenizers, shakers, vibrating mixers, ultrasonic generators, emulsifying centrifuges, colloid mills or atomizer. The homogenization can be carried out either in the reaction space by immersing the dispersing unit in the reaction mixture or outside the reaction space by continuously circulating the reaction mixture through a dispersing unit. In addition to the dispersing unit, a conventional stirrer can ensure further mixing.

The Mixing ratio (1) :( 2) can be over a very vary widely and is based on the Amingruppenichte the target products.

at Therefore, the process of the invention is organopolysiloxane (2) in amounts of preferably 20 to 500 mol, preferably 20 to 200 mol, per mole Aminoalkylsilanhydrolysat (1) used.

at discontinuous stirring processes is the dosing order uncritical, but for practical reasons Aminoalkylsilanhydrolysat (1) preferably dosed to the already inserted organopolysiloxane (2) becomes.

The Reaction (ii) between (1) and (2) is in the presence of basic Catalyst performed. After preparing the dispersion From (1) and (2), therefore, basic catalyst (3) is added.

to Carrying out the reaction (ii) of (1) with (2) in economical interesting periods becomes a basic catalyst (3) requires the redistribution of the siloxy groups strongly accelerated. In principle, all known basic catalysts can be used, as well as previously for the preparation of Aminoalkylpolysiloxanen be used. However, preference is given to alkali metal hydroxides, Alkali metal alcoholates or alkali metal siloxanolates.

Examples for alkali metal hydroxides are potassium hydroxide and sodium hydroxide.

Examples for alkali metal alcoholates are sodium methoxide and sodium ethanolate.

Examples for alkali siloxanolates are sodium siloxanolates.

The basic catalysts (3) are used in the inventive Process in an amount of preferably about 1 to 500 ppm, preferably 40 to 250 ppm, in each case based on the mixture of (1) and (2) used.

The Reaction between components (1) and (2) is preferred in Range 50 ° C to 150 ° C, preferably from 70 ° C. up to 120 ° C.

The The inventive method can during printing of the surrounding atmosphere, ie at about 1020 hPa, or at higher or lower pressures become.

The Reaction time is preferably 2 to 60 minutes.

The reaction times in the case of aminoalkylpolysiloxanes which are produced by base-catalyzed equilibration to complete equilibrium are usually several hours. Such processes are usually mapped non-continuously in the batch process, since z. B. long heating and Abkühlphasen (also in the hourly range) of the agitator against the long reaction time hardly significant. However, the situation changes significantly when the reaction time is significantly lower than said heating and cooling phases. In the case of the method according to the invention, the reaction times are usually in the range of a few minutes to about one hour. Not least because of this speed is suitable Method especially for carrying out continuous driving. In this case, the reactants and the catalyst, which are optionally brought separately by preheater to the desired temperature, continuously fed into a heated and possibly equipped with mixing elements reaction space in which the reaction takes place under adjustment of the desired residence time before the reaction products in the same Measures are continuously removed from the reaction space and the catalyst is deactivated. For this type of continuous production method, the inventive method is also well suited because the amount of volatile components in the reaction mixture is preferably very low, preferably below 1 wt .-% - areas that are normally passed only by downstream distillation process. This can be dispensed with in most cases on a vacuum driving style and purge gas streams. Such continuous processes can be carried out, for example, in loop reactors, kneaders, extruders, batch batch reactors, and batch reactor cascades, flow tubes, tubular reactors, microreactors, or centrifugal pumps, or in any combination thereof.

Prefers is the reaction of the invention at the clear point stopped, d. H. a largely clear mixture is achieved when it has a Monitek haze value of ≤ 3.7 ppm. The turbidity value is measured with the OPTICAL ANALYZER from Monitec by comparative measurement against a reference suspension of kieselguhr in water. The measured value is given in ppm diatomaceous earth.

The Stopping the reaction takes place by the catalyst when it reaches of the clear point (homogeneous organopolysiloxane) is deactivated. in principle This can also be done later, but except the loss of time also an increase in volatility (and viscosity), which is not preferred is. It has surprisingly been found that the Redistribution of siloxy groups at the clearing point has progressed so far is that no appreciable amounts of adjacent aminoalkylsiloxy groups, as they are present in the hydrolyzate (1) are detectable. The catalyst (3) can be deactivated with all neutralizing agents that have been used for these purposes so far.

The Deactivation of the basic catalyst can be achieved by the addition of Neutralizing agents are made with the basic catalysts Form salts. Such neutralizing agents may, for. B. Be carboxylic acids or mineral acids. Prefers are carboxylic acids, such as methanesulfonic acid, acetic acid, Propanoic acid and hexadecane and octadecanoic acid.

The deactivation of the basic catalyst can, however, be carried out by the addition of neutralizing agents which form salts with the basic catalysts which are soluble in the amine oils obtained and thus do not produce any turbidity. Examples of such neutralizing agents are long-chain carboxylic acids which are liquid at room temperature, such as n-octanoic acid, 2-ethylhexanoic acid, n-nonanoic acid and oleic acid, hexadecanoic or octadecanoic acid, carbonic acid esters, such as propylene carbonate, or carboxylic anhydrides, such as octenylsuccinic anhydride. Further examples are triorganosilyl phosphates, preferably trimethylsilyl phosphates, and triorganophosphates, preferably mixtures of mono-, di- and Triisotridecylphosphaten (available under the name ^® Hordaphos MDIT in Fa. Clariant). Preferred trimethylsilphosphates are compositions consisting essentially of 0-50% by weight of monosilyl phosphate of the formula: [(CH ₃ ) ₃ SiO] (HO) ₂ P = O 20-100% by weight of disilyl phosphate of the formula: [(CH ₃ ) ₃ SiO] ₂ (HO) P = O 0-70 wt .-% trisilyl phosphate of the formula: [(CH ₃ ) ₃ SiO] ₃ P = O wherein the total amount is 100 wt .-%, used. The necessary amount of neutralizing agent depends on the amount of basic catalysts used (3) and is preferably 0.05 to 0.50 Ge .-%, preferably 0.15 to 0.30 wt .-%, each based on the total weight of the reaction mixture. The neutralization can be carried out before or after the cooling of the reaction mixture.

erhalten,
wobei R, A, x und y die oben dafür angegebene Bedeutung haben, z 0 oder 1 ist,
mit der Maßgabe, dass durchschnittlich mindestens zwei Reste A und mindestens zwei R¹O-Reste pro Molekül enthalten sind.The aminoalkylpolysiloxanes according to the invention are preferably those of units of the general formula

receive,
where R, A, x and y are as defined above, z is 0 or 1,
with the proviso that on average at least two radicals A and at least two R ¹ O radicals are contained per molecule.

Preferred in the process according to the invention as aminoalkylpolysiloxanes are those of the general formula HO (ARSiO) _m (R ₂ SiO) _n H (VI) receive,
wherein R, A, m and n have the meaning given above.

The have aminoalkylpolysiloxanes invention at 25 ° C, preferably a viscosity of at least 100 mPa · s, preferably 1000-500000 mPa · s, more preferably 5000-200000 mPa · s.

Preferably they contain 0.01-0.80, preferably 0.03-0.60 mEqu. Amine base per g of aminoalkylpolysiloxanes. Particularly preferred is the Range 0.05-0.40 mEq./g.

The obtained by the process according to the invention Aminoalkylpolysiloxanes have a residual volatility of preferably less than 1% by weight, preferably less than 0.7% by weight, more preferably less than 0.5% by weight. The residual volatility is a thermally determined value and is defined as the Amount of volatiles in wt .-% when heated a sample of 5 g at 120 ° C in a time of 60 min (120 ° C / 5 g / 60 min).

A large part of the volatile constituents are cyclic siloxanes, which in addition to higher cycles octamethyltetrasiloxane (D ₄ ) is included.

The aminoalkylpolysiloxanes obtained by the process according to the invention preferably have a content of octamethyltetrasiloxane (D ₄ ) of less than 0.3% by weight, preferably of less than 0.2% by weight.

Example 1:

400 g of an OH-terminated polydimethylsiloxane having the viscosity 1000 mm ² / s (25 ° C) with 8.0 g of a likewise OH-terminated hydrolyzate of Aminopropylmethyldimethoxysilane with an NH ₂ concentration of 8.5 meq / g and a average chain length of 22 siloxy units mixed turbulently, so that a highly opaque dispersion, which is no longer transparent in a layer thickness of more than 2 cm, so that a barcode (barcode) is no longer recognizable arises.

While stirring with a paddle stirrer at about 300 U / min. the mixture is heated to 100 ° C and starts the reaction of the two components by adding 40 mg of KOH in the form of a 20% solution in ethanol. The dispersion clears after 10 minutes and the catalyst is immediately deactivated with 42 mg of acetic acid. The weakly cloudy by potassium acetate reaction product is filtered clear after cooling. It is an amine oil having a viscosity of 6700 mm ² / s (25 ° C), an amine density of 0.17 meq / g and a volatility (5 g / lh / 120 ° C) of only 0.2 wt. % receive.

In the high-resolution ²⁹ Si NMR spectrum, only about 3 mol% of aminopropylsiloxy block structures of the hydrolyzate are detectable at -22.40 ppm at this very short reaction time, whereas the main peak of the isolated aminopropylsiloxy units reappears at -22.53 ppm. Thus, the good separation of Aminoalkylbausteine used is proven to a state where only minimal amounts of volatile cyclic siloxanes are formed.

It is an aminoalkylsiloxane with randomly distributed dimethylsiloxane and aminopropylmethylsiloxane units and terminal Silanol groups obtained.

Comparative Experiment 1: analog US 3,890,269 (= DE 2 339 761 A )

In a manner not according to the invention, Example 1 is carried out with 400 g of a mixture of octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane instead of an OH-terminated polydimethylsiloxane. Under otherwise identical conditions, the dispersion initially obtained 10 minutes after catalysis with KOH solution at 100 ° C is not clear. The siloxane mixture deactivated by acetic acid separates into 2 phases. The measured volatility (5 g / lh / 120 ° C) is 49 wt .-%. A useful aminoalkylorganopolysiloxane can not be obtained in this way. The deposition of used as starting material Aminoalkylsilanhydrolysat shows that this has reacted only insufficiently with the cyclosiloxanes. The measured after homogenization of the dispersion viscosity of 3.2 mm ² / s (25 ° C) also proves a completely insufficient polymer structure.

Comparative experiment 2: with aminoalkylsilane instead of aminoalkylsilane hydrolyzate (1)

Example 1 is repeated with the proviso that 11 g of aminopropylmethyldimethoxysilane and not 8.0 g of its hydrolyzate are used. The content of aminoalkyl groups is identical to 0.17 meq / g. Following the same procedure, an aminoalkylsiloxane product with 1780 mm ² / s (25 ° C), which has a volatility of 1.3 wt .-%, which corresponds to 6 times the value of Example 1 of the invention. The reaction progress can not be identified by a clear point, since the reaction mixture is clear from the beginning. An optical indicator is therefore missing.

Comparative experiment 3: Determination of stability

From 400 g of an OH-terminated polydimethylsiloxane having a degree of polymerization of 38 and 11 g Aminopropylmethyldimethoxysilan be in a conventional manner with 400 ppm Benzyltrimethylammoniumhydroxyd (40% solution in MeOH) in 5 hours at 100 ° C and then heating at 150 ° C 380 g of an aminopropylmethyl / dimethylpolysiloxane having a viscosity of 3850 mm ² / s (25 ° C). Nuclear resonance analysis shows a MeO / OH ratio of the chain ends of 42/58.

In each case 50 g of this polymer and of the aminoalkylsiloxane from Example 1 are subjected to an accelerated aging process at 70 ° C. for 7 days. The results are summarized in Table 1. Table 1: example 1 Comparative experiment 3 Viscosity after preparation [mm ² / s] at 25 ° C 6700 3850 Viscosity after annealing [mm ² / s] at 25 ° C 11300 14400 Changes in % +69 +374

The Conventionally prepared aminoalkylsiloxane shows in the rapid test a more than 5 times greater viscosity increase compared to the product from Example 1. It is thus far less stable as an aminoalkylsiloxane prepared according to the invention.

Example 2:

400 g of an OH-terminated polydimethylsiloxane having a viscosity of 5900 mm ² / s (25 ° C) are mixed with 5 g of Aminoalkylsilanhydrolysats from Example 1, so that a highly opaque dispersion is formed, and as stirred there is heated to 90 ° C. After addition of 100 mg of a 20% solution of KOH in ethanol, the very cloudy dispersion becomes clear after 21 minutes. The catalyst is shortly thereafter, as described in Example 1, deactivated, the pale turbid amine oil clear filtered. At an amine content of 0.10 meq / g, the product has a volatility of 0.3% by weight and a viscosity of 19100 mm ² / s (25 ° C).

A sample of this product is annealed for 7 days at 70 ° C to test the tendency for self-condensation of the siloxanol groups. The annealing causes a viscosity increase to 30800 mm ² / s (25 ° C), equivalent to an average chain extension of only about 15%.

The Aminoalkylsiloxane thus obtained with randomly distributed dimethylsiloxane and aminopropylmethylsiloxane units and terminal Silanol groups is therefore storage-stable.

Example 3:

In order to test the feasibility of the process under even more mild conditions, Example 2 is repeated at 60 ° C, but the KOH amount is doubled. The reaction mixture takes 54 minutes to reach the clear point, whereupon the catalyst is deactivated (analogously to Example 2). At naturally the same amine content, the volatility is again 0.3 wt .-%, the viscosity 18700 mm ² / s (25 ° C). In ²⁹ Si NMR, block structures are no longer detectable at -22.40 ppm, and their redistribution is therefore smooth even at mild 60 ° C, long before the equilibrium state is reached, which is clearly visible in the low volatility.

Example 4:

400 g of a methyl-terminated polydimethylsiloxane having a viscosity of 2000 mm ² / s (25 ° C) are mixed well with 10.0 g of an OH-terminated hydrolyzate of aminoethylaminopropylmethyldimethoxysilane at 2460 mm ² / s (25 ° C), so that a strong opaque dispersion is formed, and heated to 100 ° C with stirring (300 rev / min.). After addition of 60 mg of KOH dissolved in ethanol, the initially very turbid mixture becomes clear after 9 minutes. The catalyst is then deactivated with 85 mg of acetic acid. After cooling, potassium acetate is filtered off, giving a clear oil having a viscosity of 1100 mm ² / s (25 ° C.), an amine density of 0.25 meq / g and only 0.3% by weight volatility (5 g / l). lh / 120 ° C).

Example 5:

Example 4 is repeated with 400 g of a low-viscosity OH-terminated polydimethylsiloxane with about 40 siloxy units instead of the highly viscous silicone oil. For catalysis also 20 mg of sodium methylate dissolved in methanol are used. The clear reaction product is neutralized after 47 minutes with 0.24 g of Hordaphos MDIT. The approach achieved a viscosity of 140 mm ² / s (25 ° C) at a volatility of 0.7 wt .-% and an amine value of 0.26 (meq / g).

Example 6:

100 g of the OH-terminated polydimethylsiloxane used in Example 5 and 300 g of another OH-terminated polydimethylsiloxane at 560 mm ² / s (25 ° C) is mixed with 10 g of the same Aminoalkylsilanhydrolysats (from Example 4), so that a highly opaque Dispersion is formed, and heated to 85 ° C with stirring. Addition of the same amount of sodium methylate (Example 5) provides a clear reaction mixture after 64 minutes, which is immediately neutralized with 0.24 g of Hordaphos MDIT. The resulting amine oil now has a viscosity of 790 mm ² / s (25 ° C.) at 0.8% by weight volatility and an amine number of 0.26 (meq / g).

Example 7:

98.79 vol .-% of an OH-terminated polydimethylsiloxane having a viscosity of 5900 mm ² / s (25 ° C) and 1.18 vol .-% of Aminoalkylsilanhydrolysats from Example 1 were continuously mixed in a tubular reactor to an opaque dispersion and with the addition of 0.02% by volume of sodium methylate dissolved in methanol (30%) in the tubular reactor (internal diameter 80 mm, height 500 mm, volume about 2.5 L) at 80 ° C reactor internal temperature continuously reacted, the reaction mixture is short became clear before reaching the exit from the reaction space. The deactivation of the catalyst was carried out with 0.01 vol .-% acetic acid.

Product leakage, product cooling, and continuous catalyst deactivation occurred after an average residence time of 25 minutes. After a running time of the reactor of 6 h, this was turned off and the product container is emptied. This gave a colorless oil with a kinematic viscosity of 13300 mm ² / s (25 ° C), a volatility (150 ° C / 5 g / 60 min) of 0.20 wt .-% and an amine number of 0.10 ( meq./g). In ²⁹ Si NMR no block structures are detectable at -22.40 ppm.

Example 8: Determination of volatile octamethylcyclotetrasiloxane content (D ₄ ):

As a meaningful parameter for estimating the unwanted volatility of a siloxane product (content of thermally removable substances from a polymeric product), the spectrometrically detectable content of octamethylcyclotetrasiloxane (D ₄ ) can be used. A suitable reference is the quotient of the integral for D ₄ at -19.3 ppm in ²⁹ Si NMR to the total integral of all dialkylsiloxy units (total D) in the range from -10 to -25 ppm. Since D _{4 represents} only part of the volatile constituents in the product, this percentage is usually also lower than the thermally determined value of residual volatility.

For the aminoalkylpolysiloxanes of Examples 1 to 6 (B1-B6) and Comparative Experiments 1 and 2 (V1 and V2), the results are summarized in Table 2. Table 2: B1 B2 B3 B4 B5 B6 V1 V2 D ₄ / total D in% by weight 0.1 0.1 0.1 0.1 0.3 0.3 27 0.5

Also, the low content of volatile D ₄ in the unheated aminoalkylpolysiloxanes shows the superiority of the method according to the invention.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - EP 382366 A [0003]
• US 3890269 [0004, 0052]
• - DE 2339761 A [0004, 0052]
• WO 2006/015740 [0011]

Claims (9)

A process for preparing aminoalkylpolysiloxanes by (i) mixing (1) aminoalkylsilane hydrolyzate of the general formula (AR _a SiO _{(3-a) / 2} ) _m (R ¹ O _1/2 ) _p (I) and (2) linear and branched organopolysiloxane of units of the general formula

and until a dispersion is obtained, wherein R is the same or different and is a monovalent, optionally halogenated hydrocarbon radical having 1 to 18 carbon atoms, R ^{1 is} a hydrogen atom or an alkyl radical having 1 to 4 carbon atoms, which may contain one or two separate oxygen atoms A is a monovalent SiC-bonded hydrocarbon radical containing 1 to 4 separate basic nitrogen atoms, a is 0 or 1, m is an integer from 2 to 500 and p is an integer of at least 2, x 0, 1, 2 or 3, y is 0 or 1, with the proviso that on average at least 10 silicon atoms per molecule are contained in the organopolysiloxane (2), (ii) reaction of aminoalkyl silane hydrolyzate (1) and organopolysiloxane (2) in the dispersion in the presence of a basic catalyst (3) until a substantially clear mixture is obtained and (iii) stopping the reaction by neutralization of the basic one n catalyst (3). A method according to claim 1, characterized in that as Aminoalkylsilanhydrolysat (1) those of the general formula HO (ARSiO) _m H (III) is used, wherein R, A and m have the meaning given in claim 1. A method according to claim 1 or 2, characterized in that as the organopolysiloxane (2) those of the general formula HO (R ₂ SiO) _n H (IV) is used, wherein R has the meaning given in claim 1 for this purpose and n is an integer from 20 to 500. Method according to claim 1, 2 or 3, characterized that as basic catalyst (3) such selected from the group of alkali metal hydroxides, alkali metal alcoholates and Alkalimetallsiloxanolaten is used. Method according to one of claims 1 to 4, characterized in that as neutralizing agent carboxylic acids, Triorganosilylphosphate and triorganophosphates are used. Method according to one of claims 1 to 5, characterized in that (ii) the reaction is carried out at a temperature of 50 to 150 ° C and a reaction time of 2 to 60 minutes. Method according to one of claims 1 to 6, characterized in that the method is carried out continuously becomes. Method according to one of claims 1 to 7, characterized in that as Aminoalkylpolysiloxane those of the general formula HO (ARSiO) _m (R ₂ SiO) _n H (VI) wherein R, A and m are as defined in claim 1 and indicated herein, and n has the meaning given in claim 3 hereof. Aminoalkylpolysiloxanes of the general formula HO (ARSiO) _m (R ₂ SiO) _n H (VI) wherein R, A and m have the meaning given in claim 1 and for this purpose and n has the meaning given in claim 3, with the proviso that the aminoalkylpolysiloxanes have a content of octamethylcyclotetrasiloxane (D ₄ ) of less than 0.3% by weight exhibit.